1. Field of the Invention
The present invention relates generally to a vibration damper with adjustable damping force. The vibration damper includes a cylinder filled with damping medium. In the cylinder, a piston rod with a piston is realized so that the piston rod can move axially and the piston can divide the cylinder into two working chambers. The damping valve can operate as a function of pressure. The damping force of the damping valve can be modified by means of an actuator against a spring force on a shutoff valve body.
2. Background Information
German Patent No. 41 14 305 A1 discloses a known vibration damper similar to that described above. The damping force characteristic of the vibration damper depends essentially on the tuning or adjustment of a spring which spring acts on a shutoff valve body. The sizes of the respective pressurized surfaces also have a very significant influence on the opening behavior of the damping valve.
Relatively flat damping force characteristics are altogether typical of a valve of this construction, and these damping force characteristics run essentially parallel to one another in the range of relatively high flow velocities of the damping medium. In this context, reference is made to German Patent No. 41 04 110 A1, FIG. 13. The very simple response to the requirement for greater damping forces at higher volume flows is to set an overall harder damping force characteristic. Such a design naturally requires a relatively high switching frequency of the damping valve. Depending on the direction of action of the actuator, there can also be an increased consumption of energy, namely when the actuator sets a higher damping force characteristic with a greater energy supply.